This invention relates to apparatus for and method of disassembling (or partially disassembling) nailed together wooden structures, such as wooden pallets or the like.
Generally, wood pallets are used in many industries for the handling of various goods or materials. A pallet typically is a platform on which goods are stacked or otherwise supported with the pallet serving as a stacking platform or support so as to facilitate the handling of the entire load of goods stacked on the pallet by means of a forklift. A wood pallet generally consists of a plurality of spaced wood stringer members exending generally in parallel direction. Oftentimes the stringer members are made of 2.times.4 lumber and are stood on edge so that their widest sides extend vertically. A number of wooden slats made, for example, of 1.times.4 lumber or the like, are placed transversely across the stringers and are nailed to the upper and lower faces of the stringers. The pallets may be rectangular or square (when viewed in plan) and may have slats nailed to the top and bottom faces of the stringers or only to the top of the stringer members. It will be appreciated that with the pallet resting on the floor and with the load supported on the upper slats, the lifting tines of a forklift may be readily inserted into the pallet between the stringers below the top slats so as to facilitate lifting of the pallet together with its load.
In use, pallets oftentimes become damaged thus necessitating their repair or disposal. In order to economically repair pallets, it is necessary that the damaged wood members be readily removed and replaced. It is especially difficult to remove a stringer because all of the slats nailed thereto must be removed. To this end, apparatus, such as is shown in U.S. Pat. No. 3,869,780, has become available in the pallet industry. In general, the apparatus shown in the above-noted patent operates by moving a pallet to be repaired past a stationary nail cutter (e.g., a pair of overlapping rotary cutting wheels) carried on a buck or cantilevered support so as to shear the nails holding the slats to one edge of a respective stringer. By turning the pallet over, by aligning the same stringer with the nail cutter, and by repeating the nail cutting operation, all of the nails holding a stringer in place within the pallet may be cut thus permitting the removal of the stringer. U.S. Pat. No. 4,152,819 discloses an improvement of the apparatus shown in the above-noted '780 patent in which the circular knife blades are particularly well-suited to cut hardened, machine driven nails. However, while the above apparatus did represent an improvement over prior pallet repair techniques, the apparatus of the '780 patent was relatively slow as it took ten or more seconds to cut the nails on each side of each stringer, and the apparatus of both prior patents required that the pallet be turned over and repositioned so as to cut the nails holding the slats to both faces of a stringer.
In recent years, the cost of the lumber required to construct a pallet has steadily increased. Pallet refurbishing operators have known for some time that lumber from damaged pallets can be used in the construction or repair of other pallets. Heretofore, however, it often was not feasible to manually disassemble damaged pallets for the purpose of salvaging lumber therefrom due to the labor costs involved in properly disassembling a pallet.
Reference may also be made to such prior U.S. Pat. Nos. as 2,593,843, 3,512,242 and 3,740,815 which disclose various prior pallet disassembling apparatus. In general, these prior apparatus function by pulling the slats from the stringer so as to disassemble the pallet. However, it will be appreciated that with the slats pulled from the stringers, that sharp nails extend from the slats and must be removed thus resulting in further labor costs and presenting a significant hazard to personnel handling the disassembled lumber.
The apparatus shown in the above-noted U.S. Pat. No. 3,869,780 has been used in the total disassembly or stripping of pallets. However, the relatively slow operating speed of the apparatus and the necessity for multiple repositioning the pallet relative to the nail cutting blades results in high labor costs for totally disassembling pallets thus eliminating, at least in part, some of the advantages gained by disassembling damaged pallets for the purpose of reclaiming lumber.
Among the several objects and features of this invention may be noted the provision of apparatus for and method of disassembling wooden pallets in an efficient and economical manor substantially without causing damage to the wooden members;
The provision of such apparatus which permits a pallet to be disassembled to be readily placed in the apparatus and which requires a minimum of repositioning of the pallet during operation of the apparatus;
The provision of such apparatus which may be readily adjusted to accomodate pallets of various configurations and sizes;
The provision of such apparatus in which certain of the nail cutting means are self-aligned with the nails in a respective stringer upon cutting the nails once the nail cutters have been generally aligned with the respective stringers so as to effect nail cutting substantially without damage to or interference from the wood members of the pallet;
The provision of such an apparatus which aids workmen by automatically separating the stringers from the slats and by automatically removing wood members from the apparatus;
The provision of such apparatus which is of rugged construction and which is reliable in operation;
The provision of such apparatus and method which enables the slats to be cut loose from the top and bottom of the stringers without repositioning or turning the pallet; and
The provision of such apparatus and method which requires minimum amount of labor and time to use.
Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.